Heat Exchanger and Refrigeration Cycle Apparatus

ABSTRACT

A heat exchanger includes: a fin extending in a widthwise direction along an air flow direction and extending in a longitudinal direction crossing the air flow direction; and a heat transfer tubepassing through the fin. The fin has a through hole. The fin includes a planar portion, and a first protruding portion, a second protruding portion and a third protruding portion protruding from the planar portion. The first protruding portion is curved along the longitudinal direction. The second protruding portion is located between the first protruding portion and the through hole and surrounds the through hole. The third protruding portion extends linearly in the longitudinal direction and is located on a leeward side relative to the first protruding portion and the second protruding portion in the air flow direction.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger and a refrigerationcycle apparatus.

BACKGROUND ART

Conventionally, there has been a fin-and-tube-type heat exchangerincluding a fin and a heat transfer tube passing through the fin. Forexample, in a heat exchanger described in Japanese Patent Laying-OpenNo. 2005-77083 (PTL 1), a fin includes a seat portion (planar portion),and peak and valley portions. The seat portion is concentrically formedaround an outer circumference of a fin collar to guide air flowingaround a heat transfer tube to thereby reduce a wake region. The seatportion is provided with opened front and rear portions. The peak andvalley portions are continuously formed between the fin collars toprovide airflow variation.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laying-Open No. 2005-77083

SUMMARY OF INVENTION Technical Problem

In the heat exchanger described in the literature above, the peak andvalley portions are continuously formed along an air flow direction, andthus, a boundary layer starting from the peak portion is formed.Therefore, the valley portion forms a dead water region. As a result, alocal heat transfer coefficient in the valley portion decreases, whichleads to a decrease in heat transfer coefficient of the entire fin. Inaddition, stress concentrates on the planar portion provided with nopeak and valley portions, and thus, the fin has insufficient strength.Furthermore, when the heat exchanger functions as an evaporator, frosttends to form on the heat exchanger on the windward side of air blown bya fan or the like.

The present disclosure has been made in view of the problem above, andan object of the present disclosure is to provide a heat exchanger and arefrigeration cycle apparatus that can improve heat transfer efficiency,improve strength of a fin, and suppress a decrease in frost formationresistance.

Solution to Problem

A heat exchanger of the present disclosure includes: a fin extending ina widthwise direction along an air flow direction and extending in alongitudinal direction crossing the air flow direction; and a heattransfer tube passing through the fin. The fin has a through hole. Theheat transfer tube is inserted in the through hole. The fin includes aplanar portion, and a first protruding portion, a second protrudingportion and a third protruding portion protruding from the planarportion. The first protruding portion is curved along the longitudinaldirection. The second protruding portion is located between the firstprotruding portion and the through hole and surrounds the through hole.The third protruding portion extends linearly in the longitudinaldirection and is located on a leeward side relative to the firstprotruding portion and the second protruding portion in the air flowdirection.

Advantageous Effects of Invention

According to the heat exchanger of the present disclosure, the firstprotruding portion and the second protruding portion protrude from theplanar portion, and thus, an influence of a dead water region can besuppressed. Therefore, an improvement in heat transfer coefficient ofthe fin can be achieved. In addition, the strength of the fin can beimproved by the first protruding portion, the second protruding portionand the third protruding portion. Furthermore, the third protrudingportion is located on the leeward side relative to the first protrudingportion and the second protruding portion in the air flow direction, andthus, the formation of frost on the fin can be suppressed on thewindward side. Therefore, a decrease in frost formation resistance canbe suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view schematically showing a configuration of aheat exchanger according to a first embodiment.

FIG. 2 is a cross-sectional view of a region A in FIG. 1 taken alongline II-II.

FIG. 3 is an end view taken along line in FIG. 2 .

FIG. 4 is an end view taken along line IV-IV in FIG. 2 .

FIG. 5 is a refrigerant circuit diagram showing a refrigeration cycleapparatus according to the first embodiment.

FIG. 6 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a second embodimentcorresponding to FIG. 2 .

FIG. 7 is an end view taken along line VII-VII in FIG. 6 .

FIG. 8 is an end view taken along line VIII-VIII in FIG. 6 .

FIG. 9 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a third embodimentcorresponding to FIG. 2 .

FIG. 10 is an end view taken along line X-X in FIG. 9 .

FIG. 11 is an end view taken along line XI-XI in FIG. 9 .

FIG. 12 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a fourth embodimentcorresponding to FIG. 2 .

FIG. 13 is an end view taken along line XIII-XIII in FIG. 12 .

FIG. 14 is an end view taken along line XIV-XIV in FIG. 12 .

DESCRIPTION OF EMBODIMENTS

Embodiments will be described hereinafter with reference to thedrawings. In the following description, the same or correspondingportions are denoted by the same reference characters and descriptionthereof will not be repeated.

First Embodiment

A configuration of a heat exchanger HE according to a first embodimentwill be described with reference to FIGS. 1 to 4 .

Referring to FIGS. 1 and 2 , heat exchanger HE includes a fin F and aheat transfer tube P. Fin F extends in a widthwise direction D1 along anair flow direction D0 and extends in a longitudinal direction D2crossing air flow direction D0. Fin F is formed in a substantiallyrectangular shape. Heat transfer tube P passes through fin F. Heattransfer tube P is a circular pipe. Fin F has a through hole TH. Throughhole TH is formed in a circular shape. Heat transfer tube P is insertedin through hole TH.

In the present embodiment, heat exchanger HE includes a plurality offins F and a plurality of heat transfer tubes P. The plurality of fins Fare stacked on top of each other at intervals. Heat transfer tube Ppasses through the plurality of fins F in a direction D3 of stacking ofthe plurality of fins F. Each of the plurality of fins F has a pluralityof through holes TH. The plurality of through holes TH are aligned inlongitudinal direction D2 of fin F. The plurality of through holes THare spaced apart from each other in longitudinal direction D2 of fin F.

Widthwise direction D1 of fin F is orthogonal to longitudinal directionD2. Widthwise direction D1 of fin F may be a horizontal direction.Longitudinal direction D2 of fin F may be an up-down direction (verticaldirection). Direction D3 of stacking of fins F is orthogonal towidthwise direction D1 and longitudinal direction D2 of fin F.

Heat transfer tube P includes a plurality of heat transfer portions P1and a plurality of connection portions P2. Each of the plurality of heattransfer portions P1 passes through the plurality of fins F. Each of theplurality of heat transfer portions P1 is inserted in the plurality ofthrough holes TH in direction D3 of stacking of the plurality of fins F.The plurality of heat transfer portions P1 are formed linearly. Each ofthe plurality of heat transfer portions P1 extends in direction D3 ofstacking of the plurality of fins F.

Each of the plurality of connection portions P2 is a portion thatconnects the plurality of heat transfer portions P1 outside theplurality of fins F. Each of the plurality of connection portions P2 isformed in a U-shape. Each of the plurality of connection portions P2connects two of the plurality of heat transfer tubes P that are adjacentto each other in longitudinal direction D2 of fin F. Each of theplurality of connection portions P2 is connected to ends of theplurality of heat transfer portions P1 in direction D3 of stacking ofthe plurality of fins F. The plurality of heat transfer portions P1 aredisposed in multiple stages in longitudinal direction D2 of fin F. Inthe present embodiment, the plurality of heat transfer portions P1 aredisposed in four stages along longitudinal direction D2 of fin F.

The plurality of heat transfer portions P1 are connected by theplurality of connection portions P2 as follows. Heat transfer portion P1in the first stage is connected to heat transfer portion P1 in thesecond stage by connection portion P2 on the back side in direction D3of stacking of the plurality of fins F. Heat transfer portion P1 in thesecond stage is connected to heat transfer portion P1 in the third stageby connection portion P2 on the front side in direction D3 of stackingof the plurality of fins F. Heat transfer portion P1 in the third stageis connected to heat transfer portion P1 in the fourth stage byconnection portion P2 on the back side in direction D3 of stacking ofthe plurality of fins F. In this way, heat transfer tube P is configuredto meander in longitudinal direction D2 of fin F.

A structure of fin F will be described in detail with reference to FIGS.2 to 4 . Fin F includes a planar portion SP, a first protruding portionMP1, a second protruding portion MP2, a third protruding portion MP3,and a fin collar FC. Planar portion SP is formed in a planar shape.Planar portion SP is formed in a flat plate shape.

First protruding portion MP1, second protruding portion MP2 and thirdprotruding portion MP3 protrude from planar portion SP. In the presentembodiment, first protruding portion MP1, second protruding portion MP2and third protruding portion MP3 protrude from planar portion SP in thesame direction. In the present embodiment, fin F includes a plurality offirst protruding portions MP1 and a plurality of second protrudingportions MP2.

First protruding portion MP1 is curved along longitudinal direction D2of fin F. First protruding portion MP1 is curved to protrude inlongitudinal direction D2 of fin F. First protruding portion MP1 has aportion extending along longitudinal direction D2 of fin F. Firstprotruding portion MP1 also has a portion extending along widthwisedirection D1 of fin F. First protruding portion MP1 is located to bedisplaced from the center of through hole TH in widthwise direction D1of fin F. In the present embodiment, first protruding portion MP1 isformed in a circular arc shape. In the present embodiment, firstprotruding portions MP1 have the same width.

The plurality of first protruding portions MP1 are aligned inlongitudinal direction D2 of fin F. In the present embodiment, fourfirst protruding portions MP1 are located between two through holes THin longitudinal direction D2 of fin F. Two first protruding portions MP1are located on each of the upper side and the lower side of one throughhole TH in longitudinal direction D2 of fin F.

Two first protruding portions MP1 located on the upper side of onethrough hole TH in longitudinal direction D2 of fin F are located to beadjacent to each other in longitudinal direction D2 of fin F. Two firstprotruding portions MP1 located on the lower side of one through hole THin longitudinal direction D2 of fin F are located to be adjacent to eachother in longitudinal direction D2 of fin F.

Two first protruding portions MP1 located to be adjacent to each otherare curved to the same side along longitudinal direction D2. Also, twofirst protruding portions MP1 located to sandwich one through hole TH inlongitudinal direction D2 of fin F are curved to the opposite sidesalong longitudinal direction D2. Two first protruding portions MP1located close to the upper through hole TH between two through holes THare curved to protrude downward. Two first protruding portions MP1located close to the lower through hole TH between two through holes THare curved to protrude upward. The outer first protruding portion MP1 ofthe two first protruding portions MP1 curved to protrude downward isspaced apart from the outer first protruding portion MP1 of the twofirst protruding portions MP1 curved to protrude upward.

The plurality of first protruding portions MP1 are formed in the sameshape except for the direction in which first protruding portions MP1are curved along longitudinal direction D2 of fin F. The plurality offirst protruding portions MP1 have the same radius of curvature. Therespective centers of curvature of the plurality of first protrudingportions MP1 are linearly aligned with each other in longitudinaldirection D2 of fin F. The plurality of first protruding portions MP1have the same width. The plurality of first protruding portions MP1 havethe same length.

Each of the plurality of first protruding portions MP1 is longer thaneach of the plurality of second protruding portions MP2 in widthwisedirection D1 of fin F. In longitudinal direction D2 of fin F, each ofthe plurality of first protruding portions MP1 is located betweencorresponding ones of the plurality of second protruding portions MP2.The respective centers of curvature of the plurality of first protrudingportions MP1 are linearly aligned with the respective centers of theplurality of second protruding portions MP2 in longitudinal direction D2of fin F.

The inner first protruding portion MP1 of the two first protrudingportions MP1 located on the upper side of through hole TH inlongitudinal direction D2 of fin F is adjacent to second protrudingportion MP2. The inner first protruding portion MP1 of the two firstprotruding portions MP1 located on the lower side of through hole TH inlongitudinal direction D2 of fin F is adjacent to second protrudingportion MP2.

Second protruding portion MP2 is located between first protrudingportion MP1 and through hole TH. Second protruding portion MP2 surroundsthrough hole TH. Second protruding portion MP2 is formed in an annularshape. Second protruding portion MP2 protrudes from planar portion SPmore than first protruding portion MP1.

The plurality of second protruding portions MP2 are formed in the sameshape. The respective centers of the plurality of second protrudingportions MP2 are aligned linearly in longitudinal direction D2 of fin F.The plurality of second protruding portions MP2 have the same width. Theplurality of second protruding portions MP2 have the same diameter.

Third protruding portion MP3 extends linearly in longitudinal directionD2 of fin F. Third protruding portion MP3 extends continuously from oneend to the other end of fin F in longitudinal direction D2. Thirdprotruding portion MP3 is located on the leeward side relative to firstprotruding portion MP1 and second protruding portion MP2 in air flowdirection D0. Third protruding portion MP3 is spaced apart from firstprotruding portion MP1 and second protruding portion MP2 in widthwisedirection D1 of fin F. Third protruding portion MP3 is located on aleeward end of fin F in widthwise direction D1.

In the present embodiment, no protruding portion is located on thewindward side relative to first protruding portion MP1 and secondprotruding portion MP2 in air flow direction D0. The windward side offin F is at a height position lower than that of the leeward side of finF.

First protruding portion MP1, second protruding portion MP2 and thirdprotruding portion MP3 protrude from planar portion SP less than fincollar FC.

Fin collar FC is formed in a cylindrical shape. Heat transfer tube P isinserted in fin collar FC. The outer circumferential surface of heattransfer tube P fits onto the inner circumferential surface of fincollar FC. Fin collar FC protrudes from planar portion SP. In thepresent embodiment, fin collar FC protrudes from planar portion SP inthe same direction as that of first protruding portion MP1, secondprotruding portion MP2 and third protruding portion MP3.

Fin collar FC includes a circumferential wall and a flange. Thecircumferential wall protrudes from planar portion SP. The flangeextends outward from the circumferential wall. The flange is provided atthe edge of the circumferential wall opposite to planar portion SP. Inthe present embodiment, fin F includes a plurality of fin collars FC.

A configuration of a refrigeration cycle apparatus 100 including heatexchanger HE according to the first embodiment will be described withreference to FIG. 5 . Refrigeration cycle apparatus 100 is, for example,an air conditioner or a refrigerator. The first embodiment will describean air conditioner as an example of refrigeration cycle apparatus 100.Refrigeration cycle apparatus 100 includes a refrigerant circuit RC,refrigerant, a controller CD, and air blowers 6, 7. Refrigeration cycleapparatus 100 includes a refrigerant circulation device RCD. Refrigerantcirculation device RCD is configured to circulate refrigerant forperforming heat exchange with air in heat exchanger HE. The firstembodiment will describe refrigeration cycle apparatus 100 including acompressor 1 incorporated as refrigerant circulation device RCD.Refrigerant circulation device RCD may be a refrigerant pump.

Refrigerant circuit RC includes compressor 1, a four-way valve 2, anoutdoor heat exchanger 3, a pressure reducing valve 4, and an indoorheat exchanger 5. Heat exchanger HE described above may be applied to atleast one of outdoor heat exchanger 3 and indoor heat exchanger 5.Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, and indoor heat exchanger 5 are connected by a pipe.Refrigerant circuit RC is configured to circulate the refrigerant.Refrigerant circuit RC is configured to perform a refrigeration cycle inwhich the refrigerant circulates while changing its phase.

Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, controller CD, and air blower 6 are housed in anoutdoor unit 101. Indoor heat exchanger 5 and air blower 7 are housed inan indoor unit 102.

Refrigerant circuit RC is configured such that the refrigerantcirculates in order of compressor 1, four-way valve 2, outdoor heatexchanger (condenser) 3, pressure reducing valve 4, indoor heatexchanger (evaporator) 5, and four-way valve 2 during a coolingoperation. Refrigerant circuit RC is also configured such that therefrigerant circulates in order of compressor 1, four-way valve 2,indoor heat exchanger (condenser) 5, pressure reducing valve 4, outdoorheat exchanger (evaporator) 3, and four-way valve 2 during a heatingoperation.

The refrigerant flows through refrigerant circuit RC in order ofcompressor 1, the condenser, pressure reducing valve 4, and theevaporator.

Controller CD is configured to control each device of refrigerationcycle apparatus 100 by, for example, performing calculations orproviding instructions. Controller CD is electrically connected tocompressor 1, four-way valve 2, pressure reducing valve 4, air blowers6, 7, and the like and is configured to control the operations thereof.

Compressor 1 is configured to compress the refrigerant for performingheat exchange with the air in heat exchanger HE. Compressor 1 isconfigured to compress the sucked refrigerant and discharge thecompressed refrigerant. Compressor 1 may be configured to have avariable capacity. Compressor 1 may be configured to have a capacitychanging through the adjustment of the rotation speed of compressor 1based on an instruction from controller CD.

Four-way valve 2 is configured to switch a refrigerant flow such thatthe refrigerant compressed by compressor 1 flows to outdoor heatexchanger 3 or indoor heat exchanger 5. Four-way valve 2 is configuredsuch that the refrigerant discharged from compressor 1 flows to outdoorheat exchanger (condenser) 3 during the cooling operation. Four-wayvalve 2 is also configured such that the refrigerant discharged fromcompressor 1 flows to indoor heat exchanger (evaporator) 5 during theheating operation.

Outdoor heat exchanger 3 is configured to exchange heat between therefrigerant flowing inside outdoor heat exchanger 3 and the air flowingoutside outdoor heat exchanger 3. Outdoor heat exchanger 3 is configuredto function as the condenser that condenses the refrigerant during thecooling operation and function as the evaporator that evaporates therefrigerant during the heating operation.

Pressure reducing valve 4 is configured to reduce pressure by expandingthe refrigerant condensed by the condenser. Pressure reducing valve 4 isconfigured to reduce the pressure of the refrigerant condensed byoutdoor heat exchanger (condenser) 3 during the cooling operation andreduce the pressure of the refrigerant condensed by indoor heatexchanger (evaporator) 5 during the heating operation. Pressure reducingvalve 4 is, for example, a solenoid valve.

Indoor heat exchanger 5 is configured to exchange heat between therefrigerant flowing inside indoor heat exchanger 5 and the air flowingoutside indoor heat exchanger 5. Indoor heat exchanger 5 is configuredto function as the evaporator that evaporates the refrigerant during thecooling operation and function as the condenser that condenses therefrigerant during the heating operation.

Air blower 6 is configured to blow outdoor air to outdoor heat exchanger3. In other words, air blower 6 is configured to supply air to outdoorheat exchanger 3. Air blower 6 may be configured to adjust the amount ofthe air flowing around outdoor heat exchanger 3 through the adjustmentof the rotation speed of air blower 6 based on an instruction fromcontroller CD, thereby adjusting an amount of heat exchange between therefrigerant and the air.

Air blower 7 is configured to blow indoor air to indoor heat exchanger5. In other words, air blower 7 is configured to supply air to indoorheat exchanger 5. Air blower 7 may be configured to adjust the amount ofthe air flowing around indoor heat exchanger 5 through the adjustment ofthe rotation speed of air blower 7 based on an instruction fromcontroller CD, thereby adjusting an amount of heat exchange between therefrigerant and the air.

Next, an operation of refrigeration cycle apparatus 100 will bedescribed with reference to FIG. 5 . In FIG. 5 , the solid arrowsindicate a refrigerant flow during the cooling operation, and the dashedarrows indicate a refrigerant flow during the heating operation.

Refrigeration cycle apparatus 100 can selectively perform the coolingoperation and the heating operation. During the cooling operation, therefrigerant circulates through refrigerant circuit RC in order ofcompressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, indoor heat exchanger 5, and four-way valve 2. Duringthe cooling operation, outdoor heat exchanger 3 functions as thecondenser. Heat is exchanged between the refrigerant flowing throughoutdoor heat exchanger 3 and the air blown by air blower 6. During thecooling operation, indoor heat exchanger 5 functions as the evaporator.Heat is exchanged between the refrigerant flowing through indoor heatexchanger 5 and the air blown by air blower 7.

During the heating operation, the refrigerant circulates throughrefrigerant circuit RC in order of compressor 1, four-way valve 2,indoor heat exchanger 5, pressure reducing valve 4, outdoor heatexchanger 3, and four-way valve 2. During the heating operation, indoorheat exchanger 5 functions as the condenser. Heat is exchanged betweenthe refrigerant flowing through indoor heat exchanger 5 and the airblown by air blower 7. During the heating operation, outdoor heatexchanger 3 functions as the evaporator. Heat is exchanged between therefrigerant flowing through outdoor heat exchanger 3 and the air blownby air blower 6.

Next, a function and effect of the first embodiment will be described.

In heat exchanger HE according to the first embodiment, first protrudingportion MP1 and second protruding portion MP2 protrude from planarportion SP, and thus, the effect of a dead water region can besuppressed. Therefore, a heat transfer coefficient of fin F can beimproved. Also, the strength of fin F can be improved by firstprotruding portion MP1, second protruding portion MP2 and thirdprotruding portion MP3. Furthermore, third protruding portion MP3 islocated on the leeward side relative to first protruding portion MP1 andsecond protruding portion MP2 in the air flow direction, and thus, theformation of frost on fin F can be suppressed on the windward side.Therefore, a decrease in frost formation resistance can be suppressed.

The suppression of a decrease in frost formation resistance allows forsuppression of a decrease in the volume of air passing through fin F dueto frost formed on fin F. Thus, when heat exchanger HE functions as theevaporator, a decrease in the amount of heat absorbed by the evaporatorcan be suppressed. As a result, a decrease in heating ability can besuppressed. Therefore, a decrease in comfort can be suppressed.

In addition, second protruding portion MP2 is located between firstprotruding portion MP1 and through hole TH and surrounds through holeTH. Therefore, the strength of fin F can be improved so as to surroundthrough hole TH by second protruding portion MP2.

Second Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a second embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thefirst embodiment.

The structure of fin F of heat exchanger HE according to the secondembodiment will be described with reference to FIGS. 6 to 8 .

Fin F includes a fourth protruding portion MP4. Fourth protrudingportion MP4 protrudes from planar portion SP. In the present embodiment,fourth protruding portion MP4 protrudes from planar portion SP in thesame direction as that of first protruding portion MP1, secondprotruding portion MP2 and third protruding portion MP3.

Fourth protruding portion MP4 extends linearly in longitudinal directionD2 of fin F. Fourth protruding portion MP4 continuously extends from oneend to the other end of fin F in longitudinal direction D2. Fourthprotruding portion MP4 is located on the windward side relative to firstprotruding portion MP1 and second protruding portion MP2 in air flowdirection D0. Fourth protruding portion MP4 is spaced apart from firstprotruding portion MP1 and second protruding portion MP2 in widthwisedirection D1 of fin F. Fourth protruding portion MP4 is located on aleeward end of fin F in widthwise direction D1.

Fourth protruding portion MP4 protrudes from planar portion SP less thanthird protruding portion MP3. Fourth protruding portion MP4 extendsparallel to third protruding portion MP3. Third protruding portion MP3and fourth protruding portion MP4 are located to sandwich firstprotruding portion MP1 and second protruding portion MP2.

Fourth protruding portion MP4 protrudes from planar portion SP less thansecond protruding portion MP2. Second protruding portion MP2 protrudesfrom planar portion SP less than third protruding portion MP3.

Next, the function and effect of the second embodiment will bedescribed.

In heat exchanger HE according to the second embodiment, fourthprotruding portion MP4 extends linearly in longitudinal direction D2 offin F. Thus, the strength of fin F can be improved in longitudinaldirection D2 of fin F by fourth protruding portion MP4.

In addition, fourth protruding portion MP4 is located on the windwardside relative to first protruding portion MP1 and second protrudingportion MP2 in air flow direction D0. Furthermore, fourth protrudingportion MP4 protrudes from planar portion SP less than third protrudingportion MP3. Therefore, the formation of frost on fin F can besuppressed on the leeward side.

In heat exchanger HE according to the second embodiment, fourthprotruding portion MP4 protrudes from planar portion SP less than secondprotruding portion MP2, and second protruding portion MP2 protrudes fromplanar portion SP less than third protruding portion MP3. Therefore, theformation of frost on fin F can be suppressed on the leeward side.

Third Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a third embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thesecond embodiment.

The structure of fin F of heat exchanger HE according to the thirdembodiment will be described with reference to FIGS. 9 to 11 .

Fourth protruding portions MP4 extend linearly in longitudinal directionD2 of fin F. Fourth protruding portions MP4 are spaced apart from eachother in longitudinal direction D2 of fin F. Fourth protruding portionsMP4 are separated from each other in longitudinal direction D2 of fin F.Fourth protruding portions MP4 are intermittently located inlongitudinal direction D2 of fin F, between first protruding portionsMP1 facing each other.

Fourth protruding portion MP4 is located to be displaced from firstprotruding portion MP1 and second protruding portion MP2 in widthwisedirection D1 of fin F. Fourth protruding portion MP4 is located so asnot to overlap first protruding portion MP1 and second protrudingportion MP2 in widthwise direction D1 of fin F.

Next, the function and effect of the third embodiment will be described.In heat exchanger HE according to the third embodiment, fourthprotruding portion MP4 is located to be displaced from first protrudingportion MP1 and second protruding portion MP2 in widthwise direction D1of fin F. Thus, the strength of fin F can be improved as fourthprotruding portion MP4 is located at a location on which a stress tendsto concentrate, where no first protruding portion MP1 and secondprotruding portion MP2 are formed.

Also, first protruding portion MP1 is not affected by the dead waterregion in the wake of fourth protruding portion MP4. Therefore, the heattransfer coefficient of fin F can be improved.

Fourth Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a fourth embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thesecond embodiment.

The structure of fin F of heat exchanger HE according to the fourthembodiment will be described with reference to FIGS. 12 to 14 .

First protruding portion MP1 is longer on its leeward side than on itswindward side with respect to the center of through hole TH in widthwisedirection D1 of fin F. First protruding portion MP1 has a larger area onthe leeward side than on the windward side with respect to the center ofthrough hole TH in widthwise direction D1 of fin F.

Next, the function and effect of the fourth embodiment will bedescribed.

In heat exchanger HE according to the fourth embodiment, firstprotruding portion MP1 is longer on its leeward side than on itswindward side with respect to the center of through hole TH in widthwisedirection D1 of fin F. As a result, the formation of frost on thewindward side of first protruding portion MP1 can be suppressed.

It should be understood that the embodiments disclosed herein areillustrative and non-restrictive in every respect. The scope of thepresent disclosure is defined by the terms of the claims, rather thanthe description above, and is intended to include any modificationswithin the scope and meaning equivalent to the terms of the claims.

REFERENCE SIGNS LIST

-   -   1 compressor; 2 four-way valve; 3 outdoor heat exchanger; 4        pressure reducing valve; 5 indoor heat exchanger; 100        refrigeration cycle apparatus; D0 flow direction; D1 widthwise        direction; D2 longitudinal direction; F fin; HE heat exchanger;        MP1 first protruding portion; MP2 second protruding portion; MP3        third protruding portion; MP4 fourth protruding portion; P heat        transfer tube; SP planar portion; TH through hole.

1. A heat exchanger comprising: a fin extending in a widthwise directionalong an air flow direction and extending in a longitudinal directioncrossing the air flow direction; and a heat transfer tube passingthrough the fin, the fin having a through hole, the heat transfer tubebeing inserted in the through hole, the fin comprising a planar portion,and a first protruding portion, a second protruding portion and a thirdprotruding portion protruding from the planar portion, the firstprotruding portion being curved along the longitudinal direction, thesecond protruding portion being located between the first protrudingportion and the through hole and surrounding the through hole, and thethird protruding portion extending linearly in the longitudinaldirection and being located on a leeward side relative to the firstprotruding portion and the second protruding portion in the air flowdirection.
 2. The heat exchanger according to claim 1, wherein the fincomprises a fourth protruding portion protruding from the planarportion, and the fourth protruding portion extends linearly in thelongitudinal direction, is located on a windward side relative to thefirst protruding portion and the second protruding portion in the airflow direction, and protrudes from the planar portion less than thethird protruding portion.
 3. The heat exchanger according to claim 2,wherein the fourth protruding portion protrudes from the planar portionless than the second protruding portion, and the second protrudingportion protrudes from the planar portion less than the third protrudingportion.
 4. The heat exchanger according to claim 2, wherein the fourthprotruding portion is located to be displaced from the first protrudingportion and the second protruding portion in the widthwise direction. 5.The heat exchanger according to claim 1, wherein the first protrudingportion is longer on its leeward side than on its windward side withrespect to a center of the through hole in the widthwise direction.
 6. Arefrigeration cycle apparatus comprising: the heat exchanger accordingto claim 1; and a refrigerant circulation device, the refrigerantcirculation device being configured to circulate refrigerant forperforming heat exchange with air in the heat exchanger.
 7. A heatexchanger comprising: a fin extending in a widthwise direction andextending in a longitudinal direction crossing the widthwise direction;and a heat transfer tube passing through the fin, the fin having athrough hole, the heat transfer tube being inserted in the through hole,the fin comprising a planar portion, and a first protruding portion anda second protruding portion protruding from the planar portion, thefirst protruding portion being curved along the longitudinal direction,and the second protruding portion being located between the firstprotruding portion and the through hole and surrounding the throughhole.